During oil and gas drilling, well completion, and production, waste water (also called production and flow-back water) is produced. Flow-back water is a waste water stream that flows out of the well after the hydraulic fracturing process is completed. Production water is a salty waste water stream that flows out of the well in conjunction with the oil and or natural gas that the well is producing. Flow-back and production water commonly contain propant sand (sand that is used to hold production reservoir fractures open for oil and gas flow, after the hydraulic fracturing pressure is released), completion chemical and oil mixtures that form semi-solid gels, hydrocarbons, and production reservoir formation solids. Normally, flow-back and production waste water is transported, by truck, from the well to a disposal site or recycling center. At disposal sites, trucks will offload the water by pumping it through a filter, for example a bag filter, followed by a series of separate settling tanks. Once most of the solids and hydrocarbons are removed the waste water is filtered again and pumped into a deep disposal injection well. Waste water recycling centers use the same type of pre-treatment systems to filter and settle hydrocarbon liquids, solids, and semi-solids.
In a typical disposal operation, bag filtration is used for the filtering system. The bag filtration removes solid and semi-solid contaminants that are suspended in the water pumped from the trucks. The bag filtration system is typically located downstream from where the trucks offload and discharge their fluid cargo and upstream from a series of settling tanks. The operators must periodically remove the bag filters from housings and replace them with new bag filters. Such bag filter handling and disposal increase the costs of treating water from gas and oil production sites.
Typically bag filters will fill up and require changing after filtering 100 to 200 barrels of water. Prior to disposal of used bags, operators will dump out collected solids and place the bags on a contaminant containment rack to allow gravity drainage of oil, hydrocarbon liquids and semisolids from the bag. The process is messy, hard to control from an environmental standpoint, and expensive.
The apparatus and method in the present disclosure eliminates the use of bag filters and the associated cost and mess related to such bag filter process. Further, the present disclosure removes solids from fluid in an efficient and cost effective manner. The apparatus of the present disclosure as constructed is both durable and long lasting, and requires little or no maintenance to be provided by the user throughout its operating life. In order to enhance the market appeal, the apparatus of the present disclosure should also be of inexpensive construction to thereby afford the broadest possible market. Finally, it is also an objective that all the aforesaid advantages and objectives to be achieved without incurring any substantial relative disadvantage.